Anatomy of Neck Muscles

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which muscle pulls the neck of the mandible forward along with the articular disc?

Temporalis

Masseter

Lateral pterygoid (correct)

Medial pterygoid

What is the primary function of the posterior fibers of the Temporalis muscle?

Protrusion of the mandible

Elevation of the mandible

Rotation of the mandible

Retraction of the mandible (correct)

At what age do teeth begin to erupt?

At 6 years of age

At 2 years of age

Around 6 months after birth (correct)

At birth

How many incisors are present in each jaw?

4 (central and lateral incisors) Signup and view all the answers

What covers the tongue?

Mucous membrane Signup and view all the answers

What divides the tongue into right and left halves?

Median fibrous septum Signup and view all the answers

How is the upper surface of the tongue divided?

By a V-shaped sulcus called the sulcus terminalis Signup and view all the answers

What is the frenulum of the tongue?

A fold of mucous membrane that connects the tongue to the floor of the mouth Signup and view all the answers

What is the origin of the sternocleidomastoid muscle?

Manubrium sterni and medial 3rd of clavicle Signup and view all the answers

Which nerve innervates the thyrohyoid muscle?

Hypoglossal nerve (CN XII) Signup and view all the answers

What is the action of the scalene muscles when acting unilaterally?

Elevates first rib and laterally flexes and rotates cervical part of vertebral column to the same side Signup and view all the answers

What are the muscles included in the infrahyoid muscles?

Thyrohyoid, Omohyoid, Sternohyoid, Sternothyroid Signup and view all the answers

Which muscle is responsible for depressing the hyoid bone and larynx?

Sternohyoid Signup and view all the answers

What is the insertion point of the sternocleidomastoid muscle?

Mastoid process of temporal bone and occipital bone Signup and view all the answers

What are the actions of the sternocleidomastoid muscle when contracting bilaterally?

Cervical flexion and head extension Signup and view all the answers

What is the origin of the scalene muscles?

TP of 3rd to 6th cervical vertebrae Signup and view all the answers

What is the origin of the Rectus Capitis Lateralis muscle?

Transverse process of atlas (C1) Signup and view all the answers

What is the insertion point of the Rectus Capitis Lateralis muscle?

Jugular process of occipital bone Signup and view all the answers

Which nerves innervate the Rectus Capitis Lateralis muscle?

Anterior rami of 1st and 2nd cervical nerves (C1-C2) Signup and view all the answers

What action does the Rectus Capitis Lateralis muscle perform unilaterally?

Laterally flexes the head Signup and view all the answers

What is the origin of the Rectus Capitis Anterior muscle?

Lateral mass and transverse process of atlas (C1) Signup and view all the answers

What is the bilateral action of the Longus Capitis muscle?

Head flexion Signup and view all the answers

Where does the Superior Oblique of Longus Colli originate?

Anterior tubercles of transverse processes of C3-C5 vertebrae Signup and view all the answers

What is the origin of the Vertical portion of Longus Colli?

Anterior surfaces of bodies of lower three cervical and superior three thoracic vertebrae Signup and view all the answers

Study Notes

Neck Muscles

The thyrohyoid muscle is innervated by C1 fibers via the hypoglossal nerve (CN XII).

Scalene Muscles

The scalene muscles have three parts: anterior, medius/middle, and posterior.
They originate from the transverse processes of the 3rd to 6th cervical vertebrae.
They insert into the 1st and 2nd ribs.
They are innervated by C4, 5, and 6 (anterior rami of cervical nerves).
When acting unilaterally, they elevate the 1st rib/2nd rib and laterally flex and rotate the cervical part of the vertebral column to the same side.
When acting bilaterally, they cause cervical flexion.

Sternocleidomastoid Muscle

The sternocleidomastoid muscle originates from the manubrium sterni and the medial 1/3 of the clavicle.
It inserts into the mastoid process of the temporal bone and the occipital bone.
It is innervated by the spinal part of the accessory nerve (CN 11) and C2 and 3.
When contracting bilaterally, it causes cervical flexion and head extension.
When contracting unilaterally, it causes ipsilateral flexion and contralateral rotation.

Suprahyoid and Infrahyoid Muscles

The suprahyoid muscles include the digastrics, mylohyoid, stylohyoid, and geniohyoid (DMSG).
The infrahyoid muscles include the thyrohyoid, omohyoid, sternothyroid, and sternohyoid (TOSS).
The sternothyroid muscle is responsible for depressing the hyoid bone and larynx.
The digastrics muscle elevates the hyoid bone and depresses the mandible.
The mylohyoid muscle elevates the hyoid bone and floor of the mouth during swallowing.

Rectus Capitis Lateralis Muscle

The rectus capitis lateralis muscle originates from the transverse process of the atlas (C1).
It inserts into the jugular process of the occipital bone.
It is innervated by the anterior rami of the 1st and 2nd cervical nerves (C1-C2).
When acting bilaterally, it flexes the head on the neck.
When acting unilaterally, it laterally flexes the head.

Rectus Capitis Anterior Muscle

The rectus capitis anterior muscle originates from the lateral mass and transverse process of the atlas (C1).
It inserts into the basilar part of the occipital bone.
It is innervated by the anterior rami of the 1st and 2nd cervical nerves (C1-C2).
It flexes the head.

Longus Capitis Muscle

The longus capitis muscle originates from the anterior tubercles of the transverse processes of C3-C6.
It inserts into the basilar part of the occipital bone.
It is innervated by the anterior rami of the 1st to 3rd cervical nerves (C1-C3).
It causes head flexion bilaterally and ipsilateral head rotation unilaterally.

Longus Colli Muscle

The longus colli muscle has three segments: superior oblique, vertical portion, and inferior oblique.
The superior oblique originates from the anterior tubercles of the transverse processes of C3-C5 vertebrae.
The vertical portion originates from the anterior surfaces of the bodies of the lower three cervical and superior three thoracic vertebrae (C5-T3).
The inferior oblique originates from the posterior fibers of the temporalis.

Mastigation

The lateral pterygoid muscle pulls the neck of the mandible forward along with the articular disc.
The temporalis, masseter, and medial pterygoid muscles are involved in the elevation of the mandible.
The lateral pterygoid muscle is involved in the protrusion of the mandible, drawing the lower teeth forward over the upper teeth.
The posterior fibers of the temporalis muscle are involved in the retraction of the mandible.

Teeth Development

Deciduous teeth begin to erupt about 6 months after birth.
All deciduous teeth have erupted by the end of 2 years.
The lower jaw teeth usually appear first.
There are 4 incisors, 2 canines, and 4 molars in each jaw.
Teeth begin to erupt at 6 years of age, and the last tooth, the 3rd molar, typically erupts between 17 and 30 years of age.

Tongue

The tongue is covered in a mucous membrane.
The tongue is divided into right and left halves by a median fibrous septum.
The upper surface of the tongue is divided into anterior and posterior parts by a V-shaped sulcus called the sulcus terminalis.
The frenulum of the tongue is a fold of mucous membrane that connects the undersurface of the tongue to the floor of the mouth.
The intrinsic muscles of the tongue are confined to the tongue and are not attached to bone.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn about the thyrohyoid muscle, scalene muscles, and their innervation and insertion points in the human neck.